Today I upgraded my Wordpress from 2.2.1 to 2.2.2. They didn't change many things, it was only a security update. So, being not a major update, it is possible to copy the new wordpress files overwriting the old files from your installation, without being necessary to update your database. This worked well, but here I want to point the other method to update your wordpress blog, using a plugin that will upgrade your blog automatically to the latest version. The plugin can be downloaded here and the detailed instructions to using it are here.
The steps which the plugin does;
1. Backs up the files and database and makes them available for
2. Downloads the latest files from http://wordpress.org/latest.zip and unpack it.
3. Puts the site in maintenance mode, deactivates all active plugins and will enable them at the end.
4. Upgrades wordpress files and give you the possibility to upgrade the database.
5. Re-activates the plugins.
If you don't want to see/use the intermediate steps let the plugin to be run in an automated mode, and you don't have to carry about, you will see only the final page and you are invited to check your blog.
That's all .
Minor problems in my case:
1. the plugin had no rights to write in wordpress install directory, so I had to fix this first, and rerun the update
2. all plugins were activated but only the sidebar plugin was not activated at the end, so, it was necessary to activate it manually